The present invention relates to switches and in particular relates to multiple switches with a unitary contact layer operating as a collection bus and which further comprises multiple conductor segments, each representative of a different switch, which are singly or collectively operable by the application of a single transverse touching force to thereby perform multiple switching using the single applied touching force.
Touch switch devices have been known and are incorporated to effect switching in numerous types of electronic instruments. One type of device in which touch switches may be used to particular advantage are musical instruments and specifically keyboards for those musical instruments. The novel multiple switch device of the present invention may be used to provide either a chord keyboard or a single note keyboard.
In the chord keyboard, a number of chord switches are provided in a keyboard arrangement so that when a chord switch is depressed one or more musical notes will be generated. Each chord switch is fabricated by providing several individual electrically isolated touch switches which are oriented in close proximity so that the application of one touch force will cause several of the individual electrically isolated touch switches to be closed. One feature of the invention is that at least several of the chord switches (and hence individual electrically isolated switches comprising each chord switch) have a common switch contact. This common switch contact also provides an output bus on which two or more different signals are combined when the individual switches are closed. This dual function is made possible by the incorporation of a semiconductor composition layer between the two contacts (one of which is common to several other switches) and one of which is electrically separate from the corresponding contacts of the other switches of each individual switch.
Another significant advantage of the present invention is that a multi-musical note chord can be generated by applying but a single transverse touch force. Thereafter that chord can be altered by the addition or deletion of one or more notes simply by rolling or rotating the finger to alter the location at which the transverse touching force is applied. This causes one or more individual electrically isolated switches of the chord switch to be opened or closed. In order to accomplish this function, individual segments representing separate contacts for the individual switches are provided on each chord switch structure. These segments are then positioned in relatively close but non-contacting relationship so that the application of a single touching force effectively closes all of the switches by bringing an upper unitary conductive layer into electrical contact with each of the individual conductor segments. A different signal is coupled to each segment. These signals are then coupled through a resistive layer and are combined on the unitary conductor conductive layer (second contact for the switches).
The particular chord may be easily changed or other wise altered by the musician by simply rolling the finger which is applying the transverse touch force. This finger roll action operates to either bring the unitary first conductive layer into electrical contact with additional segments or to break the contact between the unitary conductive layer and one or more of the previously contacted segments.